Apparatus for cleaning a residual image from a photosensitive member

ABSTRACT

Residual toner particles remaining after transfer of a developed image from a photoconductive surface are cleaned therefrom by a rotatable, hollow core cleaning brush whose blades sweep loose the toner particles from the photoconductor. The brush is provided with a plurality of openings located between the blades and in communication with the core through which the loosened toner particles are withdrawn by vacuum applied to the core. Removal of the residual toner particles may be further assisted by applying a bias voltage to the brush to attract the toner particles to the brush and by using a flicker bar to loosen the toner particles from the cleaning blades.

[1 1 3,706,108 1 Dec. 19, 1972 United States Patent Taylor 1 [s41APPARATUS FOR CLEANING A OTHER PUBLICATIONS 1Q), Krause, IBMTechnical'Disclosure Bulleti Brush Cleaning Method .m c O R r .m y a AmM i 0m m R. v. FMm EE Y GV 6N. An N Ml "T l mm Lmca A U0 E .mT m mmmRP.m H U [73] Assignee: Eastman Kodak Company, Rochester, N.Y.

Primary Examiner-Leon G. Machlin 8 1970 Attamey -w. H. J. Kline andDouglas 1. Plague Appl. No.: 101,893

[22] ,Filed:

ABSTRACT Residual toner particles remaining after transfer of a [52] US.15/308 developed image from a photoconductive surface are [51] Int. Cl.....B08b 1/02 l an th r from y a rota le, h llow. c re l n- [58] Fieldof Search.15/308, 1,5, 309, 256,52, 2565; ing brush whose blades sweeploose the toner particles 117/19, 175; 1'13/637;29/121 R from thephotoconductor. The brush is provided with aplurality of openingslocated between the blades and in communication with the core throughwhich they [5 6] References Cited loosened toner particles are withdrawnby vacuum ap- UNITED STATES PATENTS plied to the core. Removal of theresidual toner particles may be further assisted by applying a biasvoltage 4/1969 Tanaka et to the brush to attract the toner particles tothe brush 3,438,706 3,278,972 Hudson and by using a flicker bar toloosen the toner particles from the cleaning blades.

6 Claims, 3 Drawing Figures P'A'TENTEDuEc 19 me TRANSFER STATIONCLARENCE R. TAYLOR INVENTOR.

ATTORNEYS APPARATUS FOR CLEANING A RESIDUAL IMAGE FROM APIIOTOSENSITIVEMEMBER BACKGROUND OF THE INVENTION charge on the photoconductiveinsulating surface-while the photoconductive. member iskept in darkness.The charged photoconductive member-is subsequently exposed to aradiation pattern to form a'latent electrostatic image. Exposure toradiation causes areas of the photoconductive insulating layer which areexposed to become conductive so that the charge in these exposed areasis dissipated. Areas not exposed to the radiation continue to act asinsulators and thus retain their electrostatic charge. The electrostaticlatent imagine is then toned by a suitable developer having tonerparticles which are attracted by the charged areas of the image to forma toner image. This toner image is then transferred to a suitablereceiver by contacting the receiver to the image bearing photoconductivesurface and applying a potential to the receiver'of opposite polarity tothe charge on the toner particles to bring about imagetransfenI-Iowever, a small amount of residual toner I particles usuallyremains on the photoconductive surface which must be removed therefromprior to the forming and transfer of subsequent imagesto prevent ghostimages from being formed. during subsequent transfers.

There are many well known methods and apparatus .for cleaningphotoconductive surfaces. One known method of cleaning a photoconductivesurface utilizes a rotating brush mounted within a housing to whichhousing a vacuum is applied to withdraw the toner particles removed fromthe photoconductive surface away from the vicinity of the brush to cleanit. One disadvantage of these prior art brush devices is that the rapidbrushing of the photoconductive surface creates an airborne toner cloud,a portion of which may escape the housing to deposit on other parts ofthe apparatus. These deposits create cleaning problems and result insmudging and smearing of the copy if the parts of the apparatus on whichthe toner particles have deposited come into contact with the receiver.

SUMMARY OF THE INVENTION airborne toner cloud surrounding a cleaningbrush.

Still another object of the invention is to provide cleaning apparatusadaptable to a great variety of 2v speeds and widths of photoconductivemembers and yet of simple design and construction, thoroughly efficientand reliablein operation, and economical to manufacture.

.located between the brush fibers which are in communication with thecore. A vacuum applied to the core withdraws the toner particles removedfrom the photoconductor by the fibrous cleaning device through theopenings between the brush fibers.

In a preferred embodiment of the invention, a cleaning brush whoseblades are made of an electrically conductive material is rotated tosweep loose the toner particles from the photoconductive surface. Anelectrical potential is applied tothe brush by means of a flicker barthat contacts the brush blades as the brush rotates. By applying apotential to the brush which is opposite in polarity to the charge onthe residual toner particles the electrostatic forces which hold thetoner particles to the photoconductive surface can be overcome so thatthe particles are removed from the photoconductive surface. The flickerbar loosens the toner particles from the brush so that they are carriedby the air flow through the openings between the brush blades and intothe hollow core of the brush.

Other objects and advantages of the invention will become more apparentfrom the detailed description of the preferred embodiment which follows.

. BRIEF DESCRIPTION OF THE DRAWING FIG. 2 is an enlarged, section viewtaken along line A 2-2 of FIG. 1, showing the cleaning apparatus ingreater detail. FIG. 3 is a section view, taken along line 3-3 of FIG.2, showing further details of the cleaning apparatus.

DESCRIPTIONOF THE PREFERRED EMBODIMENT Referring now to the drawingthere is shown an electrophotographic mechanism M, which includes anendless photoconductive belt 10, extending around spaced rollers 11 and12. The belt 10 is illustrated as I being driven by motor 13 through adrive belt 14 con-, nected to the roller 12. The belt 10 is driven inthe direction of arrow 15 past a charging station 16 which places auniform electrical charge (either positive or negative) over itsphotoconductive surface; an exposure station 17 whereat the belt isexposed to a radiation pattern, such as a light image from an original,to discharge the photoconductive surface in accordance with theradiation pattern to form an electrostatic latent image; a developingstation 18 whereat the latent image is developed by depositing tonerthereon; a transfer station 19 whereat the developed image istransferred to a receiver; and finally a novel cleaning about theperiphery of a cylinder 30 whose core,3,1 is' hollow. The brush-20 ismounted for rotation about bearings 22 and 23 and is disposed so that aportion of 'the'brushblades 21 contacts the area of the photoconductivebelt to be cleaned. Bearing 22 interconnects a housing or shroud 28 anda drive hub 25 connected to the brush cylinder 30 and bearing 23interconnects the brush cylinder and a vacuum means described in detailbelow.,A platen 24 on the side of the photoconductive belt 10 oppositethat of the brush :0 is provided to sup- I port the belt in frictionalcontactwith the brush. Alternatively, platen 24 can be replaced by aroller. The housing or shroud 28 extends around a portion. of the brush20 and, as best seen in FIG. 3, has a masked down portion 29 to providea close fit with the brush blades 21. t

Advantageously, the brush 20 is rotated. by means (not shown) attachedto the drive hub so that it moves,as shown by arrow 26, in a directionopposite to the movement of the photoconductive belt 10 at the point ofcontact therewith. Rotation of the brush 20 causes theblades 21 to knockor sweep loose the'toner particles from the photoconductive surface ofthe belt 10. Means, such as a vacuum tube 33 inserted into the hollowcore 31 of the brush cylinder has a source of vacuum (not shown) appliedthereto to draw the loosened toner particles from the blades into thecore for removal, through a series of openings or passageways .27 in thebrush cylinder 30 located betweenthe brush blades and through slotsorports of the vacuum tube 33 which are in communication with thepassageways 27. v v

The toner particles which stick to the cleaning blades 21 are carriedinto the area enclosed by the shroud 28 where they are loosened from thecleaning blades 21 by a flexible metal flicker bar 32 mounted in theshroud 28 so that it contacts the cleaning blades as the brush rotates.The toner particles removed from the cleaning bladesby the flicker bar32 are subsequently drawn off by the vacuum tube '33 through slots orports 34 located in the vacuum tube 33 or through the passageways 27 ofthe brush cylinder 30 and the ports 35 of the vacuum tube 33.

Conveniently, the cleaning blades 21 are made from an electricallyconductive rubber so that an electrical potential from source 36,opposite in polarity to the charge on the residual toner particles, canbe applied to the brush 20, which is electrically isolated from itsmounting, by means of the flicker bar 32.

Application of a bias voltage to the brush 20 of opposite polarity tothe charge on the residual toner particles attracts the residual tonerparticles to the brush by overcoming the electrostatic forces which holdthe Y 4 toner particlesto the photoconductive surface of the belt 10.

From the foregoing, the advantages of the present invention are readilyapparent. The harmful effects 5 caused by escaping airborne 'tonerparticles are reduced by providing a cleaning brush having'a hollow coreto which a vacuum is'applied so that the toner particles are drawnthrough the brush for removal. The apparatus is composed of structureswhich are small in size yet. economical to manufacture and with longlife characteristics.

, The invention has been described in detail with reference to apreferred embodimentthereof, but it will be understood'that variationsand modifications can be effected within the, spirit and scope of theinvention.

lclaimz I w 1. Cleaning apparatus for cleaning residual toner particlesfrom an irnagebearing support surface, said cleaning apparatuscomprising: 1"

a. a hollow core cleaning element having at least one blade extendingoutwardly from the exterior surface of said core and at least onepassageway communicating between the exterior and interior sur- 25 I Ifaces of said core;

' Y b. means for mounting said cleaning element so that said bladeengages theportio'n of said image bearing surface to be cleaned; c. ashroud substantially surrounding at least a por- 30 tion of saidcleaning element;

d. flicking means mounted in said shroud in interferen'ce relation tosaid blade;

e. means for moving said cleaning element and said image bearing surfacerelative to each other to remove toner particles from said image bearingsurface and for moving said cleaning element relative to said flickingmeans to remove toner particles from said cleaning element; and

f. means'for applying'a vacuum to. said core to withdraw the tonerparticles removedfrom said cleaning element by' said flicking means intosaid core through said passageway. v

2. Cleaning apparatus for cleaning residual toner particles from animage-bearing surface, said cleaning apparatus comprising! a.arotatable, hollow core cleaning brush having a plurality of. bladesspaced at substantially equal intervals about its periphery and aplurality of passageways communicating with said core and said peripheryof said cleaning brush; b. means for mounting said. brush for engagementwith said image-bearing surface; c. means for rapidly rotating saidbrush;

d. means to cause relative motion between the axis of said brush andsaid image-bearing surface;

e. a shroud substantially surrounding at least a portion of said brush;

f. flicking means mounted in said shroud in interference relation to thebrush blades to remove toner particles from said brush; and g. means forapplying a'vacuum to said core to withdraw an airstream containingtherein suspended toner particles removed from said image-bearingsurface through said passageways. 3. Cleaning apparatus as claimed inclaim 2 wherein the toner partiGles are charged to a first polarity andsaid blades of said brush are made of an electrically conductivematerial, said-cleaning apparatus further including: I

potential applying means connected to said flicking means. for applyingan electrical potential of a second opposite polarity to said brushblades to attract said toner particles to said brush from saidimage-bearing surface.

4. Cleaning apparatus as claimed in claim 2 wherein said vacuum meansincludes a vacuum tube inserted into said core of said brush, saidvacuum tube having a plurality of openings aligned with saidpassageways.

5. Apparatus as claimed in claim 4 wherein said means for mounting saidbrush includes first and second bearings, said firstbearingbeingintercon-,'

space between two adjacent blades and communicating between said coreand said periphery of said cylinder;

b. means for mounting said. brush for engagement with saidphotoconductive surface;

c. means for rapidly rotating said brush;

d. means to cause relative motion between the axis of said brush andsaid photoconductive surface;

e. a shroud substantially surrounding at least a portion of said brush;

f. an electrically conductive flicking means mounted in said shroud ininterference relation to the brush blades to remove toner particles fromsaid brush;

g. a source of electrical potential connected to said flicking means forapplying to the brush blades an electrical potential of a second andopposite polarity to that of the residual toner particles so that saidtoner particles are attracted to said brush; and

h. means for applying a vacuum to said core to withdraw the tonerparticles removed from saidphotoconductive surface by said brush andfrom said brush by said flicking meansthrough said passageways, saidmeans including a vacuum tube inserted into said core, said vacuum tubehaving a plurality of openings aligned with said passageways.

1. Cleaning apparatus for cleaning residual toner particles from animage-bearing support surface, said cleaning apparatus comprising: a. ahollow core cleaning element having at least one blade extendingoUtwardly from the exterior surface of said core and at least onepassageway communicating between the exterior and interior surfaces ofsaid core; b. means for mounting said cleaning element so that saidblade engages the portion of said image bearing surface to be cleaned;c. a shroud substantially surrounding at least a portion of saidcleaning element; d. flicking means mounted in said shroud ininterference relation to said blade; e. means for moving said cleaningelement and said image bearing surface relative to each other to removetoner particles from said image bearing surface and for moving saidcleaning element relative to said flicking means to remove tonerparticles from said cleaning element; and f. means for applying a vacuumto said core to withdraw the toner particles removed from said cleaningelement by said flicking means into said core through said passageway.2. Cleaning apparatus for cleaning residual toner particles from animage-bearing surface, said cleaning apparatus comprising: a. arotatable, hollow core cleaning brush having a plurality of bladesspaced at substantially equal intervals about its periphery and aplurality of passageways communicating with said core and said peripheryof said cleaning brush; b. means for mounting said brush for engagementwith said image-bearing surface; c. means for rapidly rotating saidbrush; d. means to cause relative motion between the axis of said brushand said image-bearing surface; e. a shroud substantially surrounding atleast a portion of said brush; f. flicking means mounted in said shroudin interference relation to the brush blades to remove toner particlesfrom said brush; and g. means for applying a vacuum to said core towithdraw an airstream containing therein suspended toner particlesremoved from said image-bearing surface through said passageways. 3.Cleaning apparatus as claimed in claim 2 wherein the toner particles arecharged to a first polarity and said blades of said brush are made of anelectrically conductive material, said cleaning apparatus furtherincluding: potential applying means connected to said flicking means forapplying an electrical potential of a second opposite polarity to saidbrush blades to attract said toner particles to said brush from saidimage-bearing surface.
 4. Cleaning apparatus as claimed in claim 2wherein said vacuum means includes a vacuum tube inserted into said coreof said brush, said vacuum tube having a plurality of openings alignedwith said passageways.
 5. Apparatus as claimed in claim 4 wherein saidmeans for mounting said brush includes first and second bearings, saidfirst bearing being interconnected to said brush and said shroud, saidsecond bearing being interconnected to said brush and said vacuum tube.6. Cleaning apparatus for cleaning residual toner particles having acharge of a first polarity thereon from a photoconductive surface, saidcleaning apparatus comprising: a. a rotatable cleaning brush, said brushcomprising a cylinder having a hollow core, a plurality of electricallyconductive blades mounted at substantially equally spaced intervalsabout the periphery of said cylinder, and a plurality of passagewayseach passageway being disposed in said cylinder in the space between twoadjacent blades and communicating between said core and said peripheryof said cylinder; b. means for mounting said brush for engagement withsaid photoconductive surface; c. means for rapidly rotating said brush;d. means to cause relative motion between the axis of said brush andsaid photoconductive surface; e. a shroud substantially surrounding atleast a portion of said brush; f. an electrically conductive flickingmeans mounted in said shroud in interference relation to the brushblades to remove toner particles from said brush; g. a source ofelectrical potential connected to said flicking means for applying tothe brush blades an electriCal potential of a second and oppositepolarity to that of the residual toner particles so that said tonerparticles are attracted to said brush; and h. means for applying avacuum to said core to withdraw the toner particles removed from saidphotoconductive surface by said brush and from said brush by saidflicking means through said passageways, said means including a vacuumtube inserted into said core, said vacuum tube having a plurality ofopenings aligned with said passageways.